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noopy7 09-05-2008 05:02 AM

Best spark plugs / wires with FE in mind?
Awesome site, first post! I'm getting ready to give my '98 Dodge Neon Sport (37k miles) a tune up for the first time since I got it about a year ago. Over the past 6 months I've been keeping track of gas mileage via doing the math when filling up. I've been noticing a gradual drop in gas mileage. I got down to about 25 MPG then I decided to change the filthy air filter. It didn't really make a difference. Air pressure in the tires were good. So I'm thinking the next step is to change the plugs and wires. Anyone out there have some advice for what brands I might want to check out as well as what brands to stay away from with FE in mind?

Thanks a bunch :)

BlackDeuceCoupe 09-05-2008 05:19 AM

I use copper core plugs - and change them every 15K miles - pick your brand.

Personally, I like Champion Copper Plus spark plugs!

For the wire sets, I prefer NGK... ;)

mavinwy 09-05-2008 10:00 AM

The best plugs I have found for my Neon (97 highline DOHC) have been the plain old champion copper plugs. This seems to be consistent with other folks on the Neon boards as well. The plug wires on these are so short, that just about any good quality brand name will do, although I went with the NGK as well and have been pleased.

If your mileage is still down, make sure that you don't have a brake dragging and that the rear wheel bearings are in good shape. Just helped a friend change his and his MPG went up by 5....and of course it was quieter without the hum of the bad bearing.

If you are running the stock "habitrail" air cleaner set up, you can also remove the cold air tube (Air cleaner to front of car) and the air will both flow better and be warm air for better MPG since you just changed the air cleaner.

Other than that, you can also do the key dance and run the may have a sensor out of range.

37k miles on a 98 though....Wow that is low. Good find since the 98's are after the head gasket upgrade.


Daox 09-05-2008 11:25 AM

I'd generally agree with the fellas. The extra money spent on fancy plugs only gives you longer change intervals. Copper works just as good as platinum or irridium, it just doesn't last as long.

noopy7 09-05-2008 05:32 PM

Great advice! I know which cold air intake you're talking about. I actually had to reattach that sucker when i replaced the air filter because it was disconnected. Doh! I'll work on that first.

However, whatdo you mean by key code dance?

Ford Man 09-05-2008 08:02 PM

I like using platinum plugs because of the 100,000+ mile change intervals and I usually just buy a good quality plug wire. I think the ones that are on my '88 Escort are the best quality Auto Zone brand. They have a lifetime warranty too. If mileage has dropped that much you should check your 02 sensor, I have had them go bad before and my mileage would drop about 25-30%. The car probably came from the factory with platinum plugs and shouldn't need changing yet.

Johnny Mullet 09-05-2008 10:45 PM

I do believe in quality parts and only use quality brand ignition parts, but when it comes down to it, fuel is ignited by spark. As long as the fuel ignites, the spark plug is doing as intended. Adding extras to a plug (Splitfire, Rapidfire, etc) does nothing for fuel economy or power.

FunkSkunk 09-05-2008 10:55 PM

along with what the others have said just get some name brand plugs and you'll be good to go. Spark plugs are the worst for building up the hype on power and MPG. Also look into the fuel filter, that could help.

mavinwy 09-10-2008 12:55 PM

Sorry for the delay getting back, was out of town for work.

The key dance is turning the key from off to on (not start) 3 times at about a secone apart each. The Check Engine Light will flash the codes stored in the computer. You can use a code reader....but if it is built in.....

Haynes manuals list what the codes mean or you can find more info on


BlackDeuceCoupe 09-10-2008 04:35 PM


Originally Posted by noopy7 (Post 59162)
However, whatdo you mean by key code dance?

This may or may not be pertinent to your car, but it's a good working example of what mavinwy is talking about... ;)


The 1980s-1990s Chrysler Computer Codes
  • Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. (On is *not* start!)
  • The "check engine" light will flash. Count the flashes Each code is a two digit code, so a (for example) 23 would be FLASH FLASH (pause) FLASH FLASH FLASH (loong pause)
  • It will never flash more than 9 times, watch for pauses!
  • 55 is end of codes - it's normal. Before you call your dealer or mechanic, consider that the blink-spacing is not always perfectly uniform, so if you see
  • 23 23, it's probably just a single 55. (Codes are not repeated.)
  • 33 is normal on earlier models if you don't have air conditioning.

John McGuire wrote: "The older Vipers will blink out diag codes with four off/on key turns. They removed the capability starting in... I think 2000, at any rate I know my 2001 requires a computer to check the codes."

On some models (such as a 1995 Neon), when the check engine light goes on, you may be able to get the codes simply by putting in the key and moving it to the RUN position; the light will blink out the codes by itself.
Please note that some codes are NOT included below, this is not a complete listing, but it IS very close to complete. It stemps from a list posted on the Mopar Mailing List, but many modifications have been made.

* Activates Power Limited/Check Engine light on some models.
IMPORTANT. Codes may be different for newer vehicles starting in the late 1990s. See the earlier section.

11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. Can cause the engine to stop working entirely with no limp-home mode.
12 Battery or computer recently disconnected
13* MAP sensor or vacuum line may not be working
14* MAP sensor voltage below .16V or over 4.96V
15 No speed/distance sensor signal
16* Loss of battery voltage detected with engine running
17 Engine stays cool too long (bad thermostat or coolant sensor?)
17 (1985 turbo only): knock sensor circuit


21 Oxygen sensor signal doesn't change (stays at 4.3-4.5V). Probably bad oxygen sensor
22* Coolant sensor signal out of range - May have been disconnected to set timing
23* Incoming air temperature sensor may be bad
24* Throttle position sensor over 4.96V (SEE NOTE #3)
25 Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached, vacuum leak found
26 Peak injector circuit voltage has not been reached (need to check computer signals, voltage reg, injectors) (SEE NOTE #4 BELOW)
27 Injector circuit isn't switching when it's told to (TBI)
OR (MPI) injector circuit #1 not switching right
OR (turbo) injector circuit #2 not switching right
OR (all 1990-) injector output driver not responding
- check computer, connections


31 Bad evaporator purge solenoid circuit or driver
32 (1984 only) power loss/limited lamp or circuit
32 EGR gases not working (1988) - check vacuum, valve
32 (1990-92, all but Turbo) computer didn't see change in air/'fuel ratio when EGR activated - check valve, vacuum lines, and EGR electrical
33 Air conditioning clutch relay circuit open or shorted (may be in the wide-open-throttle cutoff circuit)
34 (1984-86) EGR solenoid circuit shorted or open
34 (1987-1991) speed control shorted or open
35 Cooling fan relay circuit open or shorted
35 (trucks) idle switch motor fault - check connections
36 (turbo) Wastegate control circuit open or shorted
36 (3.9/5.2 RWD) solenoid coil circuit (air switching)
36 (Turbo IV) #3 Vent Solenoid open/short
37 Shift indicator light failure, 5-speed
part throttle lock/unlock solenoid driver circuit (87-89)
solenoid coil circuit (85-89 Turbo I-IV)
Trans temperature sensor voltage low (1995 and on; see NOTE 2)


41* Alternator field control circuit open or shorted
42 Automatic shutdown relay circuit open or shorted
42 Fuel pump relay control circuit
42 Fuel level unit - no change over miles
42 Z1 voltage missing when autoshutdown circuit energized (SEE NOTE #6)
43 Peak primary coil current not achieved with max dwell time
43 Cylinder misfire
43 Problem in power module to logic module interface
44 No FJ2 voltage present at logic board
44 Logic module self-diagnostics indicate problem
44 Battery temperature out of range (see Note #1!)
45 Turbo boost limit exceeded (engine was shut down by logic module)
46* Battery voltage too high during charging or charging system voltage too low
47 Battery voltage too low and alternator output too low


51 Oxygen sensor stuck at lean position (Bob Lincoln wrote: may be tripped by a bad MAP sensor system causing a rich condition, and the O2 sensor trying to compensate. The O2 sensor may still be good. The MAP assembly consists of two pieces, the valve and the vacuum transducer (round plastic unit with cylinder on top and both electrical and vacuum connections) - If you get hot rough idle and stalling, especially on deceleration, accompanied by flooded engine and difficulty restarting, that can be a bad MAP sensor causing the O2 sensor to try to compensate. If you get poor cold driveability, stumbling and bucking, and acceptable warm driving with poor gas mileage (a drop of 10 mpg or more), that is usually the O2 sensor. [Webmaster note: MAP sensors seem to die regularly.]

51 Internal logic module fault ('84 turbo only).
52 Oxygen sensor stuck at rich position (SEE NOTE #5!)
52 Internal logic module fault ('84 turbo only)
53 Logic module internal problem
54 No sync pickup signal during engine rotation (turbo only)
54 Internal logic module fault ('84 turbo only) - or camshaft sensor/distributor timing (7)
55 End of codes


61 "Baro" sensor open or shorted
62 EMR mileage cannot be stored in EEPROM
62 PCM failure SRI mile not stored
63 Controller cannot write to EEPROM
64 Catalytic converter efficiency failure
65 Power steering switch failure


88 Start of test (not usually given, don't expect it)

Bullockracing 09-10-2008 05:32 PM

NGK non-suppression plugs, and premium wires. You are not looking to remove resistance, but resistivity, which is resistance in relation to diameter. Iridium and platinum are good for longevity, as previously stated. Splitfires suck (in every vehicle I've ever tried them in at least - 6 of them). I've had good luck with AC Rapidfires - on high performance ignitions at least. I currently run NGK non-suppression Iridiums - my car doesn't take wires. I would recommend Taylor 10.4mm wires if they have a set for you, if not, get minimum 9mm wires - highest quality you can afford...

Angelus359 10-29-2010 02:31 PM

I'm using NGK iridium IX in my car... I bought a 2008 aveo with 34k miles on it... its stock coppers were horrendusly roasted... the iridium IX gave a notable improvement.

Note, most of the improvement was just "new plug" and not iridium

the NGK IX is rated for 60 thousand miles, and is a low voltage plug... that means its better for cold winter starts (which I need in chicago)

Once the engine is warm... if the plug burnt to hell... it doesn't make a difference

gone-ot 10-29-2010 04:18 PM

...don't believe that "low-resistance" wires will help your FE. While "low-resistance" wires were popular with the hot-rodders, they tend to create LOTS of "ignition-noise" STATIC which your radio will loudly announce to the listening audience.

...additionally, too little wire resistance is also detrimental to maintaining optimum inductive-discharge spark-duration time -- it effectively lets all the spark "arc" energy dump to ground almost immediately, rather than maintaining the "arc" duration for about 1,000 microseconds by "metering" the current level discharge by the coil-secondary/wire RL-time constant.

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